Driving an automobile is a major factor in the maintenance of independence and mobility among older persons. Loss of driving privileges and resultant dependencies are a greatly feared consequence of aging, which can lead to continued driving even among those at high risk of crashes. Avoidance of high- risk situations as well as attention to driving performance and other compensatory strategies are behaviors that allow older drivers with limitations to continue driving safely under proscribed circumstances. Thus, there is much interest in determining the factors that predict adoption of compensatory driving strategies. In this project, a multi-disciplinary team will determine the role of vision and cognition, perception of limitations, and alternatives to driving, in adoption of compensatory driving strategies within a 4 year, longitudinal study of an older population in Salisbury, MD. Three groups of older drivers will be identified: Group One: those with normal vision and alone; Group Three: those with both visual deficits and deficits in visual attention. All groups include those with deficits in the tests of cognition. Driving behaviors will be assessed over time, using a novel system that allows passive recording of actual driving behavior by the study participant. In particular, deficits in acuity, contrast sensitivity, visual fields, and visual attention, and changes in these measures over time, are hypothesized to affect adoption of compensatory driving strategies or driving cessation in addition, cognitive status, as well as insight into limitations, are hypothesized to be both predictors and effect modifiers of this relationship. Finally, the study will determine how adoption of compensatory driving strategies, and which strategies, affect crash risk. The specific aims are as follows: 1) To determine the driving characteristics of the cohort of older drivers, and associate patterns of driving with visual, cognitive, and perceptual characteristics. 2) To determine longitudinally how vision and cognition impairments, and change in impairments, result in adoption of compensatory driving strategies, and 3) To determine for each risk group over the four-year prospective component, the adoption of compensatory driving strategies and resulting effect on driver error rates and crash risk. This study will provide critical data on the interactive role of vision, visual attention, and cognition in changing older persons driving behaviors, and the resulting effect on driver errors and risk of crashes.